Flash lamp



Nov. 30, 1943. L. F. ANDERSON FLASH LAMP Filed Dec. 3, 1938 40 0 OXYeSE/V I IINVENTOR lesieriflzzdersom BY flu" ATTORNEY Patented Nov. 30, 1943 23357225 'msn LAMP V Lester F. Anderson, East Orange, N. 1., assignor to Wabash Appliance Corporation, Brooklyn, N. Y., a corporation of New York Application December 3, 1938, Serial No. 243,728

2 Claims. 1 (CI. 67-31) This invention relates to new and useful improvements in flash lamps such as are used in photography.

It is the object of the present invention to pro:-

duce a flash lamp of materially reduced size-as compared to flash lamps of the prior art.

Fig. 1 of the drawing illustrates the conventional wire type lamp filled with oxygen to-40 rise of a mercury column and Fig. 2 the curves l and 2 of the prior lamps and my'improved lamp, respectively.

In the customary flash lamp filled with an alu-' second. A foil type lamp requires about onethird the time of the wire type of lamp, and the height of its peak is about double that of the wire type lamp for the same amount of total actinic output.

The relatively great width and the slow rise of the characteristic curve of the wire-filled lamp permits the increase of the oxygen pressure to about 40 centimeters of mercury without endanminum foil or the like, in order to obtain an actinic output of approximately 45,000 lumen seconds, an A23 type of bulb (diameter 2%") must be used and an oxygen pressure of approximately 20, and a safe maximum of 22, centimeters rise oi mercury column maintained therein. With an A19 type bulb (diameter 2%"), only an actinic output of 22,500 lumen seconds could be obtained. Whenever an attempt was made in such lamps to obtain relatively high actinic output and at the same time uniformity of timing with reduced size bulbs or increased oxygen pressure, the glass bulbs exploded, endangering the users.

I have found that the actinic output for a given size bulb can be increased and the bulb filled with oxygen at relatively high pressure, provided that the bulb is filled with a more slowly burning combustible material than foil in conjunction with a faster priming material to maintain timing characteristics. Wire of the kind disclosed in Patent No. 2,037,101 to J. A. Van Liempt is sultable for this purpose; The flash time characteristic 01' such wire-filled lamp increases from zero intensity to the peak intensity in /1: of a gering'the user. Probably on account of the relative slowness of its development, the energy will be dissipated before it can reach proportions that would fracture the glass bulb.

With my improved flashlight bulb an actinic output of 56,000'lumen seconds can be obtained with an A19 bulb filled with oxygen to 36 cm. rise of mercury column; 40,000 lumen seconds with an A17 bulb (diameter 2%") at 38 cm. oxygen pressure; 30,000 lumen seconds, with an A15 bulb (diameter 1%") at 44 cm. oxygen pressure; and 23,000 lumen seconds with an S13 bulb (diameter 1%") at 44 cm. oxygen pressure.

What is claimed is:

1. In a flash lamp, a closed bulb containing a filling of wire, means in said bulb for igniting the wire while the bulb remains closed to the atmosphere, and a filling of oxygen in said bulb to a pressure at more than 36 cm. rise of mercury column.

2. In a flash lamp, a closed bulb containing a filling or wire, means in said bulb for igniting the wire while the bulb remains closed to the atmosphere, and a filling of oxygen in said bulb to a pressure of approximately 40 cm. rise of mercury column.

LESTER F. ANDERSON. 

